Actual source code: eptorsion2f.F90
1: ! Program usage: mpiexec -n <proc> eptorsion2f [all TAO options]
2: !
3: ! Description: This example demonstrates use of the TAO package to solve
4: ! unconstrained minimization problems in parallel. This example is based
5: ! on the Elastic-Plastic Torsion (dept) problem from the MINPACK-2 test suite.
6: ! The command line options are:
7: ! -mx <xg>, where <xg> = number of grid points in the 1st coordinate direction
8: ! -my <yg>, where <yg> = number of grid points in the 2nd coordinate direction
9: ! -par <param>, where <param> = angle of twist per unit length
10: !
11: !
12: ! ----------------------------------------------------------------------
13: !
14: ! Elastic-plastic torsion problem.
15: !
16: ! The elastic plastic torsion problem arises from the deconverged
17: ! of the stress field on an infinitely long cylindrical bar, which is
18: ! equivalent to the solution of the following problem:
19: ! min{ .5 * integral(||gradient(v(x))||^2 dx) - C * integral(v(x) dx)}
20: ! where C is the torsion angle per unit length.
21: !
22: ! The C version of this code is eptorsion2.c
23: !
24: ! ----------------------------------------------------------------------
26: module eptorsion2fmodule
27: #include "petsc/finclude/petsctao.h"
28: use petscdmda
29: use petsctao
30: implicit none
32: type(tVec) localX
33: type(tDM) dm
34: PetscReal param
35: PetscInt mx, my
36: end module
38: use eptorsion2fmodule
39: implicit none
40: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
41: ! Variable declarations
42: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
43: !
44: ! See additional variable declarations in the file eptorsion2f.h
45: !
46: PetscErrorCode ierr ! used to check for functions returning nonzeros
47: type(tVec) x ! solution vector
48: type(tMat) H ! hessian matrix
49: PetscInt Nx, Ny ! number of processes in x- and y- directions
50: type(tTao) tao ! Tao solver context
51: PetscBool flg
52: PetscInt i1
53: PetscInt dummy
55: ! Note: Any user-defined Fortran routines (such as FormGradient)
56: ! MUST be declared as external.
58: external FormInitialGuess,FormFunctionGradient,ComputeHessian
59: external Monitor,ConvergenceTest
61: i1 = 1
63: ! Initialize TAO, PETSc contexts
64: PetscCallA(PetscInitialize(ierr))
66: ! Specify default parameters
67: param = 5.0
68: mx = 10
69: my = 10
70: Nx = PETSC_DECIDE
71: Ny = PETSC_DECIDE
73: ! Check for any command line arguments that might override defaults
74: PetscCallA(PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-mx',mx,flg,ierr))
75: PetscCallA(PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-my',my,flg,ierr))
76: PetscCallA(PetscOptionsGetReal(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-par',param,flg,ierr))
78: ! Set up distributed array and vectors
79: PetscCallA(DMDACreate2d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_BOX,mx,my,Nx,Ny,i1,i1,PETSC_NULL_INTEGER,PETSC_NULL_INTEGER,dm,ierr))
80: PetscCallA(DMSetFromOptions(dm,ierr))
81: PetscCallA(DMSetUp(dm,ierr))
83: ! Create vectors
84: PetscCallA(DMCreateGlobalVector(dm,x,ierr))
85: PetscCallA(DMCreateLocalVector(dm,localX,ierr))
87: ! Create Hessian
88: PetscCallA(DMCreateMatrix(dm,H,ierr))
89: PetscCallA(MatSetOption(H,MAT_SYMMETRIC,PETSC_TRUE,ierr))
91: ! The TAO code begins here
93: ! Create TAO solver
94: PetscCallA(TaoCreate(PETSC_COMM_WORLD,tao,ierr))
95: PetscCallA(TaoSetType(tao,TAOCG,ierr))
97: ! Set routines for function and gradient evaluation
99: PetscCallA(TaoSetObjectiveAndGradient(tao,PETSC_NULL_VEC,FormFunctionGradient,0,ierr))
100: PetscCallA(TaoSetHessian(tao,H,H,ComputeHessian,0,ierr))
102: ! Set initial guess
103: PetscCallA(FormInitialGuess(x,ierr))
104: PetscCallA(TaoSetSolution(tao,x,ierr))
106: PetscCallA(PetscOptionsHasName(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-testmonitor',flg,ierr))
107: if (flg) then
108: PetscCallA(TaoMonitorSet(tao,Monitor,dummy,PETSC_NULL_FUNCTION,ierr))
109: endif
111: PetscCallA(PetscOptionsHasName(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-testconvergence',flg, ierr))
112: if (flg) then
113: PetscCallA(TaoSetConvergenceTest(tao,ConvergenceTest,dummy,ierr))
114: endif
116: ! Check for any TAO command line options
117: PetscCallA(TaoSetFromOptions(tao,ierr))
119: ! SOLVE THE APPLICATION
120: PetscCallA(TaoSolve(tao,ierr))
122: ! Free TAO data structures
123: PetscCallA(TaoDestroy(tao,ierr))
125: ! Free PETSc data structures
126: PetscCallA(VecDestroy(x,ierr))
127: PetscCallA(VecDestroy(localX,ierr))
128: PetscCallA(MatDestroy(H,ierr))
129: PetscCallA(DMDestroy(dm,ierr))
131: ! Finalize TAO and PETSc
132: PetscCallA(PetscFinalize(ierr))
133: end
135: ! ---------------------------------------------------------------------
136: !
137: ! FormInitialGuess - Computes an initial approximation to the solution.
138: !
139: ! Input Parameters:
140: ! X - vector
141: !
142: ! Output Parameters:
143: ! X - vector
144: ! ierr - error code
145: !
146: subroutine FormInitialGuess(X,ierr)
147: use eptorsion2fmodule
148: implicit none
150: ! Input/output variables:
151: Vec X
152: PetscErrorCode ierr
154: ! Local variables:
155: PetscInt i, j, k, xe, ye
156: PetscReal temp, val, hx, hy
157: PetscInt xs, ys, xm, ym
158: PetscInt gxm, gym, gxs, gys
159: PetscInt i1
161: i1 = 1
162: hx = 1.0/real(mx + 1)
163: hy = 1.0/real(my + 1)
165: ! Get corner information
166: PetscCall(DMDAGetCorners(dm,xs,ys,PETSC_NULL_INTEGER,xm,ym,PETSC_NULL_INTEGER,ierr))
167: PetscCall(DMDAGetGhostCorners(dm,gxs,gys,PETSC_NULL_INTEGER,gxm,gym,PETSC_NULL_INTEGER,ierr))
169: ! Compute initial guess over locally owned part of mesh
170: xe = xs+xm
171: ye = ys+ym
172: do j=ys,ye-1
173: temp = min(j+1,my-j)*hy
174: do i=xs,xe-1
175: k = (j-gys)*gxm + i-gxs
176: val = min((min(i+1,mx-i))*hx,temp)
177: PetscCall(VecSetValuesLocal(X,i1,k,val,ADD_VALUES,ierr))
178: end do
179: end do
180: PetscCall(VecAssemblyBegin(X,ierr))
181: PetscCall(VecAssemblyEnd(X,ierr))
182: end
184: ! ---------------------------------------------------------------------
185: !
186: ! FormFunctionGradient - Evaluates gradient G(X).
187: !
188: ! Input Parameters:
189: ! tao - the Tao context
190: ! X - input vector
191: ! dummy - optional user-defined context (not used here)
192: !
193: ! Output Parameters:
194: ! f - the function value at X
195: ! G - vector containing the newly evaluated gradient
196: ! ierr - error code
197: !
198: ! Notes:
199: ! This routine serves as a wrapper for the lower-level routine
200: ! "ApplicationGradient", where the actual computations are
201: ! done using the standard Fortran style of treating the local
202: ! input vector data as an array over the local mesh.
203: !
204: subroutine FormFunctionGradient(tao,X,f,G,dummy,ierr)
205: use eptorsion2fmodule
206: implicit none
208: ! Input/output variables:
209: type(tTao) tao
210: type(tVec) X, G
211: PetscReal f
212: PetscErrorCode ierr
213: PetscInt dummy
215: ! Declarations for use with local array:
217: PetscReal, pointer :: lx_v(:)
219: ! Local variables:
220: PetscReal zero, p5, area, cdiv3
221: PetscReal val, flin, fquad,floc
222: PetscReal v, vb, vl, vr, vt, dvdx
223: PetscReal dvdy, hx, hy
224: PetscInt xe, ye, xsm, ysm
225: PetscInt xep, yep, i, j, k, ind
226: PetscInt xs, ys, xm, ym
227: PetscInt gxs, gys, gxm, gym
228: PetscInt i1
230: i1 = 1
231: ierr = 0
232: cdiv3 = param/3.0
233: zero = 0.0
234: p5 = 0.5
235: hx = 1.0/real(mx + 1)
236: hy = 1.0/real(my + 1)
237: fquad = zero
238: flin = zero
240: ! Initialize gradient to zero
241: PetscCall(VecSet(G,zero,ierr))
243: ! Scatter ghost points to local vector
244: PetscCall(DMGlobalToLocalBegin(dm,X,INSERT_VALUES,localX,ierr))
245: PetscCall(DMGlobalToLocalEnd(dm,X,INSERT_VALUES,localX,ierr))
247: ! Get corner information
248: PetscCall(DMDAGetCorners(dm,xs,ys,PETSC_NULL_INTEGER,xm,ym,PETSC_NULL_INTEGER,ierr))
249: PetscCall(DMDAGetGhostCorners(dm,gxs,gys,PETSC_NULL_INTEGER,gxm,gym,PETSC_NULL_INTEGER,ierr))
251: ! Get pointer to vector data.
252: PetscCall(VecGetArrayReadF90(localX,lx_v,ierr))
254: ! Set local loop dimensions
255: xe = xs+xm
256: ye = ys+ym
257: if (xs .eq. 0) then
258: xsm = xs-1
259: else
260: xsm = xs
261: endif
262: if (ys .eq. 0) then
263: ysm = ys-1
264: else
265: ysm = ys
266: endif
267: if (xe .eq. mx) then
268: xep = xe+1
269: else
270: xep = xe
271: endif
272: if (ye .eq. my) then
273: yep = ye+1
274: else
275: yep = ye
276: endif
278: ! Compute local gradient contributions over the lower triangular elements
280: do j = ysm, ye-1
281: do i = xsm, xe-1
282: k = (j-gys)*gxm + i-gxs
283: v = zero
284: vr = zero
285: vt = zero
286: if (i .ge. 0 .and. j .ge. 0) v = lx_v(k+1)
287: if (i .lt. mx-1 .and. j .gt. -1) vr = lx_v(k+2)
288: if (i .gt. -1 .and. j .lt. my-1) vt = lx_v(k+1+gxm)
289: dvdx = (vr-v)/hx
290: dvdy = (vt-v)/hy
291: if (i .ne. -1 .and. j .ne. -1) then
292: ind = k
293: val = - dvdx/hx - dvdy/hy - cdiv3
294: PetscCall(VecSetValuesLocal(G,i1,k,val,ADD_VALUES,ierr))
295: endif
296: if (i .ne. mx-1 .and. j .ne. -1) then
297: ind = k+1
298: val = dvdx/hx - cdiv3
299: PetscCall(VecSetValuesLocal(G,i1,ind,val,ADD_VALUES,ierr))
300: endif
301: if (i .ne. -1 .and. j .ne. my-1) then
302: ind = k+gxm
303: val = dvdy/hy - cdiv3
304: PetscCall(VecSetValuesLocal(G,i1,ind,val,ADD_VALUES,ierr))
305: endif
306: fquad = fquad + dvdx*dvdx + dvdy*dvdy
307: flin = flin - cdiv3 * (v+vr+vt)
308: end do
309: end do
311: ! Compute local gradient contributions over the upper triangular elements
313: do j = ys, yep-1
314: do i = xs, xep-1
315: k = (j-gys)*gxm + i-gxs
316: vb = zero
317: vl = zero
318: v = zero
319: if (i .lt. mx .and. j .gt. 0) vb = lx_v(k+1-gxm)
320: if (i .gt. 0 .and. j .lt. my) vl = lx_v(k)
321: if (i .lt. mx .and. j .lt. my) v = lx_v(1+k)
322: dvdx = (v-vl)/hx
323: dvdy = (v-vb)/hy
324: if (i .ne. mx .and. j .ne. 0) then
325: ind = k-gxm
326: val = - dvdy/hy - cdiv3
327: PetscCall(VecSetValuesLocal(G,i1,ind,val,ADD_VALUES,ierr))
328: endif
329: if (i .ne. 0 .and. j .ne. my) then
330: ind = k-1
331: val = - dvdx/hx - cdiv3
332: PetscCall(VecSetValuesLocal(G,i1,ind,val,ADD_VALUES,ierr))
333: endif
334: if (i .ne. mx .and. j .ne. my) then
335: ind = k
336: val = dvdx/hx + dvdy/hy - cdiv3
337: PetscCall(VecSetValuesLocal(G,i1,ind,val,ADD_VALUES,ierr))
338: endif
339: fquad = fquad + dvdx*dvdx + dvdy*dvdy
340: flin = flin - cdiv3*(vb + vl + v)
341: end do
342: end do
344: ! Restore vector
345: PetscCall(VecRestoreArrayReadF90(localX,lx_v,ierr))
347: ! Assemble gradient vector
348: PetscCall(VecAssemblyBegin(G,ierr))
349: PetscCall(VecAssemblyEnd(G,ierr))
351: ! Scale the gradient
352: area = p5*hx*hy
353: floc = area *(p5*fquad+flin)
354: PetscCall(VecScale(G,area,ierr))
356: ! Sum function contributions from all processes
357: PetscCallMPI(MPI_Allreduce(floc,f,1,MPIU_SCALAR,MPIU_SUM,PETSC_COMM_WORLD,ierr))
358: PetscCall(PetscLogFlops(20.0d0*(ye-ysm)*(xe-xsm)+16.0d0*(xep-xs)*(yep-ys),ierr))
359: end
361: subroutine ComputeHessian(tao, X, H, Hpre, dummy, ierr)
362: use eptorsion2fmodule
363: implicit none
365: type(tTao) tao
366: type(tVec) X
367: type(tMat) H,Hpre
368: PetscErrorCode ierr
369: PetscInt dummy
371: PetscInt i,j,k
372: PetscInt col(0:4),row
373: PetscInt xs,xm,gxs,gxm
374: PetscInt ys,ym,gys,gym
375: PetscReal v(0:4)
376: PetscInt i1
378: i1 = 1
380: ! Get local grid boundaries
381: PetscCall(DMDAGetCorners(dm,xs,ys,PETSC_NULL_INTEGER,xm,ym,PETSC_NULL_INTEGER,ierr))
382: PetscCall(DMDAGetGhostCorners(dm,gxs,gys,PETSC_NULL_INTEGER,gxm,gym,PETSC_NULL_INTEGER,ierr))
384: do j=ys,ys+ym-1
385: do i=xs,xs+xm-1
386: row = (j-gys)*gxm + (i-gxs)
388: k = 0
389: if (j .gt. gys) then
390: v(k) = -1.0
391: col(k) = row-gxm
392: k = k + 1
393: endif
395: if (i .gt. gxs) then
396: v(k) = -1.0
397: col(k) = row - 1
398: k = k +1
399: endif
401: v(k) = 4.0
402: col(k) = row
403: k = k + 1
405: if (i+1 .lt. gxs + gxm) then
406: v(k) = -1.0
407: col(k) = row + 1
408: k = k + 1
409: endif
411: if (j+1 .lt. gys + gym) then
412: v(k) = -1.0
413: col(k) = row + gxm
414: k = k + 1
415: endif
417: PetscCall(MatSetValuesLocal(H,i1,row,k,col,v,INSERT_VALUES,ierr))
418: enddo
419: enddo
421: ! Assemble matrix
422: PetscCall(MatAssemblyBegin(H,MAT_FINAL_ASSEMBLY,ierr))
423: PetscCall(MatAssemblyEnd(H,MAT_FINAL_ASSEMBLY,ierr))
425: ! Tell the matrix we will never add a new nonzero location to the
426: ! matrix. If we do it will generate an error.
428: PetscCall(MatSetOption(H,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE,ierr))
429: PetscCall(MatSetOption(H,MAT_SYMMETRIC,PETSC_TRUE,ierr))
431: PetscCall(PetscLogFlops(9.0d0*xm*ym + 49.0d0*xm,ierr))
433: ierr = 0
434: end
436: subroutine Monitor(tao, dummy, ierr)
437: use eptorsion2fmodule
438: implicit none
440: type(tTao) tao
441: PetscInt dummy
442: PetscErrorCode ierr
444: PetscInt its
445: PetscReal f,gnorm,cnorm,xdiff
446: TaoConvergedReason reason
448: PetscCall(TaoGetSolutionStatus(tao,its,f,gnorm,cnorm,xdiff,reason,ierr))
449: if (mod(its,5) .ne. 0) then
450: PetscCall(PetscPrintf(PETSC_COMM_WORLD,'iteration multiple of 5\n',ierr))
451: endif
453: ierr = 0
455: end
457: subroutine ConvergenceTest(tao, dummy, ierr)
458: use eptorsion2fmodule
459: implicit none
461: type(tTao) tao
462: PetscInt dummy
463: PetscErrorCode ierr
465: PetscInt its
466: PetscReal f,gnorm,cnorm,xdiff
467: TaoConvergedReason reason
469: PetscCall(TaoGetSolutionStatus(tao,its,f,gnorm,cnorm,xdiff,reason,ierr))
470: if (its .eq. 7) then
471: PetscCall(TaoSetConvergedReason(tao,TAO_DIVERGED_MAXITS,ierr))
472: endif
474: ierr = 0
476: end
478: !/*TEST
479: !
480: ! build:
481: ! requires: !complex
482: !
483: ! test:
484: ! args: -tao_monitor_short -tao_type nls -tao_gttol 1.e-2
485: !
486: ! test:
487: ! suffix: 2
488: ! nsize: 2
489: ! args: -tao_monitor_short -tao_type lmvm -tao_gttol 1.e-2
490: !
491: ! test:
492: ! suffix: 3
493: ! args: -testmonitor -tao_type lmvm -tao_gttol 1.e-2
494: !TEST*/